Round-robin selection by destination for mail that is
delivered via the same message delivery transport. The round-robin
strategy was chosen with the intention to prevent a single
(destination) site from using up too many mail delivery resources.
However, that strategy penalized inbound mail on bi-directional
gateways. The poor suffering inbound destination would be
selected only 1/number-of-destinations of the time, even when
it had more mail than other destinations, and thus mail could
Victor Duchovni found a workaround: use different message
delivery transports, and thus avoid the starvation problem.
The Patrik Rak scheduler solves this problem by using FIFO